From 7acf0277cea0f2da89ffffcc9892bea23f618e63 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 27 Jul 2012 15:08:03 +0100 Subject: [PATCH] dm: introduce split_discard_requests This patch introduces a new variable split_discard_requests. It can be set by targets so that discard requests are split on max_io_len boundaries. When split_discard_requests is not set, discard requests are only split on boundaries between targets, as was the case before this patch. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm.c | 5 ++++- include/linux/device-mapper.h | 6 ++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 415c2803c0c9..4e09b6ff5b49 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1215,7 +1215,10 @@ static int __clone_and_map_discard(struct clone_info *ci) if (!ti->num_discard_requests) return -EOPNOTSUPP; - len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); + if (!ti->split_discard_requests) + len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti)); + else + len = min(ci->sector_count, max_io_len(ci->sector, ti)); __issue_target_requests(ci, ti, ti->num_discard_requests, len); diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index b19c1e189a68..8bdbbfce759a 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -217,6 +217,12 @@ struct dm_target { */ unsigned discards_supported:1; + /* + * Set if the target required discard request to be split + * on max_io_len boundary. + */ + unsigned split_discard_requests:1; + /* * Set if this target does not return zeroes on discarded blocks. */ -- 2.45.2